The present invention relates to fuses, and more particularly, to blade fuses for electric circuits installed in automobiles.
Typically, automobiles have fuses that are arranged between a battery and various electric components to protect circuits from excessive current. A prior art fuse is disclosed, for example, in U.S. Pat. No. 4,023,264.
FIG. 15 shows a prior art fuse 50. The fuse 50 includes an insulative fuse housing 54 and a fuse element 53, which is an H-like conductive plate. The fuse element 53 has two parallel flat base plates 51 and a fuse melting portion 52 that connects the two base plates 51. A terminal 51a is formed at the distal end of each base plate 51. The terminals 51a extend from the fuse housing 54, and portions of the fuse element 53 other than the terminals 51a are retained in the fuse housing 54. In other words, in FIG. 15, the terminals 51a are portions, which protrude downward from the lower end of the fuse housing 54.
As shown in FIG. 16, a plurality of fuses 50 are connected to a fuse box 55. Referring to FIG. 17, the fuse box 55 has a plurality of bus bars 56 that are connected to the terminals 51a of the fuses 50. Each of the bus bars 56 is bent to define a tab 57. As shown in FIG. 18, the distal end of each tab 57 is bifurcated to form two opposing divided contact pieces 57a. As shown in FIG. 18, the terminal 51a of the fuse 50 is received between the two divided contact pieces 57a so that the terminals 51a each electrically contact the corresponding tabs 57. In this manner, the fuse 50 is connected to the fuse box 55.
The increase in the number of electric components installed in recent vehicles has increased the number of protection fuses 50, which are used in the vehicles. The fuse box 55 must be relatively large to store many fuses. However, to improve the comfort of a vehicle, the interior of the vehicle is required to be enlarged. The enlargement of the vehicle interior and the installation of a large fuse box 55 are contradicting concepts and it is difficult to satisfy both demands.
With reference to FIGS. 17 and 18, when the prior art fuse 50 is connected to the fuse box 55, the height (L) from the level of the bus bar 56 to the upper end of the fuse 50 is greater than the sum of the length (M) of the tab 57 and the height (N) of the housing 54.
Since the above height (L) relates to the size of the fuse box 55, the structure of the fuse 50 hinders the production of a smaller fuse box 55.
Increasing the voltage of an automobile battery is being considered nowadays. The prior art fuse housing 54 is made of polyethelsulfone. However, in such a fuse housing 54, the required insulative resistance cannot be obtained when performing a fuse standard test with, for example, a 58V fuse. Accordingly, a fuse that is suitable for an increase of the battery voltage in the future is required.